Wheel assembly for a model airplane

Abstract

A wheel assembly for a model airplane includes a motor, a drive gear unit, a linkage, and a wheel unit. The drive gear unit includes a driven gear meshing with a driving gear connected fixedly to a spindle of the motor, and an output gear driven indirectly by the driven gear. The linkage includes a swing rod connected fixedly to the output gear, and a link connected pivotally to the swing rod. The wheel unit has a pivot end connected pivotally to an airplane body, a wheel-mounting end mounted with at least one wheel, and an intermediate portion connected pivotally to the link. The motor is operable to activate the drive gear unit so as to rotate the wheel unit between a generally horizontal idle position, and an upright landing position.

1. A wheel assembly for a model airplane, the model airplane having an airplane body, said wheel assembly being adapted to be mounted to the airplane body and comprising:
 a driving mechanism including a motor and a drive gear unit driven by said motor, said motor including a spindle and a driving gear disposed fixedly on said spindle, said drive gear unit including a driven gear meshing with said driving gear, and an output gear driven indirectly by said driven gear; 
 a linkage including a swing rod connected fixedly to said output gear at one end thereof, and a link having a first end connected pivotally to the other end of said swing rod, and a second end opposite to the first end; and 
 a wheel unit having a pivot end adapted to be connected pivotally to the airplane body, a wheel-mounting end opposite to said pivot end and said wheel-mounting end and connected pivotally to said second end of said link, wherein said wheel unit includes a sleeve, a shaft member disposed rotatably within said sleeve, and a plurality of bearings disposed between said sleeve and said shaft member for facilitating rotation of said shaft member within said sleeve, said sleeve being configured with said pivot end and a lug connected pivotally to said second end of said link, said shaft member being configured with said wheel-mounting end; 
 wherein said motor is operable to activate said drive gear unit so as to rotate said wheel unit between a generally horizontal idle position, where at least a portion of said wheel is concealed within the airplane body, and an upright landing position, where said wheel is spaced apart from the airplane body. 
 
   
   
     2. The wheel assembly as claimed in  claim 1 , wherein said driving gear is configured as a worm, said driven gear being configured as a worm gear, said drive gear unit further including a plurality of intermediate drive gears interconnecting said driven gear and said output gear such that said output gear rotates at a speed slower than that of said driven gear. 
   
   
     3. The wheel assembly as claimed in  claim 1 , further comprising a housing unit including:
 a surrounding wall adapted to be connected fixedly to the airplane body and defining an accommodating chamber, said surrounding wall being formed with a first positioning groove; and 
 a partition disposed within said accommodating chamber so as to divide said accommodating chamber into a first space for receiving said drive gear unit, and a second space for receiving said linkage, said first positioning groove being in spatial communication with said second space; 
 a top plate connected fixedly to a top portion of said surrounding wall; and 
 a shaft-coupling member extending through and disposed rotatably on said top plate and having a bottom end that is disposed in said second space and that is formed with a second positioning groove; 
 said shaft member being formed with an integral engaging member that has a rectangular cross section and that is of a shape complementary to those of said first and second positioning grooves, said engaging member engaging said first positioning groove in said surrounding wall when said wheel unit is disposed in said idle position, said engaging member engaging said second positioning groove in said shaft-coupling member when said wheel unit is disposed in said landing position.